Travelers often take a variety of approaches to navigate between a trip's origin and destination. Either as a supplement for a map or as a replacement, a person who is familiar with a route often composes driving instructions from memory and communicates them to a driver. The driver uses a written copy of the instructions as a guide to following the route. While the human based approach to navigation has benefits, it has significant limitations. In many cases, a driver simply cannot access anyone with familiarity of a route or a particular destination. And while human based driving instructions are usually the easiest to follow by a driver, frequently humans can remember or describe routes inaccurately. Human-generated instructions can be susceptible to human error. And, since individual perception is subjective, the quality and consistency of human-generated instructions can vary greatly.
As an alternative to the human based driving directions or instructions, computers can routinely generate driving instructions via conventional technologies. Commercial sources, including Internet websites and stand-alone software packages, offer a driver a list of instructions, or a driving itinerary, between one location and another. Conventional computer-generated driving instructions are generally more consistent than human-generated instructions. And with the recent proliferation of mobile computing and Internet technologies, computer-generated driving instructions are reasonably accessible in many driving situations.
Referring now to FIG. 1, an exemplary computer-generated map 1 is shown, including a proposed highlighted route 2 between two geographic points 4, 6. A set of textual, turn-by-turn, directions 8 is provided adjacent to, or overlying, a portion of the map that provide instruction to a driver about the individual turns required to navigate the highlighted route 2. FIG. 2 shows the map 1 of FIG. 1 with additional graphical information indicating regions of relative traffic slowness due to general congestion (as indicated by color key 10), construction zones 12, and road closures and detours 14, all of which may impact driving times. Maps and driving directions of this type can be created using well-known software such as Google™ maps, Yahoo!® LOCAL Maps, MapQuest®, and the like.
Computers conventionally derive these driving directions from commercially available databases that contain the geographic location of roads and intersections in a region. Conventional mapping software generates a route between user-selected start and destination points by processing the commercial database. The software typically displays a route by highlighting it on a traditional map and displaying the highlighted map through a user interface. To accompany the map, conventional software can generate textual driving instructions with what can be referred to as an itinerary module.
While conventional mapping systems are easily accessible and generally produce acceptable directions, such systems may not consider current conditions (i.e., conditions existing at the time of the trip) that can substantially impact the amount of time it will take to traverse the presented route. Rather, existing systems are often used to obtain directions for use at some point in the future (e.g., directions obtained on Friday afternoon for a trip beginning the following Monday morning). In addition, existing systems use static routing, which does not take dynamic conditions (e.g., traffic delays due to volume, weather conditions such as snow, sleet, rain, construction delays, and the like) into consideration. More often than not, the real travel time is very different from the duration estimated by these conventional systems. Indeed, many conventional systems include a disclaimer along with their directions, indicated that construction projects, traffic, weather or other events may cause conditions to differ from the mapped results.
As noted, ever changing factors such as bad weather, accidents, lane closures, general construction, rush hour, and the like can substantially affect the time required for the user to travel from point to point along the route. If such factors were considered, the total trip time could be reduced simply by making changes to (i.e., avoiding) the affected portions of the route.
It would, therefore, be desirable to provide a system that considered a plethora of real-time factors to calculate the most efficient route for a user to follow. It would also be desirable to provide a system that informs the user of the rationale for presenting a particular route, so that the user can further customize the route based on personal preferences.